The parsing routines for the language patterns (e.g. in german.pm) do not remove raw spaces from input lines. In dehyphtex.tex entries look like this:
\hyphenation{
%
%
% falsche Trennungen einfacher Wörter
%
Aa-les % Aal-es
Af-gha-nin-nen % Af-ghan-in-nen
These two entries will end up as the following keys in the $self->{exact} hash:
' aales '
' afghaninnen '
Note the leading and trailing spaces which will (usually) prevent matches.
To fix, the process_hyphenation() subs in the language.pm files would include the last line from this fragment:
sub process_hyphenation {
my ($line, $exception) = @_;
if ($line =~ /\}/) {
return 0;
}
local $_ = $line;
tr/ //d;